Figure 7

Effect of NP size on cytotoxicity.a Purified human CD4⁺T cells (>97% purity) were left untreated or incubated with different sizes (4, 13, and 20 nm) of ZnO NPs at a final concentration of 5 mM. Following culture for 22–24 h, viability was determined using PI uptake and flow cytometry,n = 4.b Cytotoxicity studies in purified human CD4⁺T cells were performed using varying concentrations (1–10 mM) of 4- and 20-nm-sized ZnO NPs,n = 4.Error bars depict SE, andasterisks indicate statistically significant differences (p < 0.05) as determined by repeated measures ANOVA